Screw standard specification
Standard screws are the norms, and each country and department has its own standards. At present, the most commonly used standards in our usual business are the following:
GB - China National Standard (GB) ANSI - American National Standard (American Standard)
DIN - German National Standard (German Standard) ASME - American Society of Mechanical Engineers Standard
JIS - Japanese National Standard (Japanese Standard) BSW - British National Standard
GB—The national standard is one of many standards in China. There are also industry standards, professional standards and departmental standards. National standards are divided into: GB (mandatory standards) and GB/T (recommended standards) and GBn (national internal standards). We usually see GB30, GB5783 and so on are mandatory standards.
In addition to some basic dimensions such as head-to-edge, head thickness, etc., the most important ones are the difference in threaded parts. Threads of GB, DIN, JIS, etc. are all in units of MM (mm), collectively referred to as metric threads. Another thread like ANSI, ASME, etc. is called the American standard thread in inches. In addition to metric and American threads, there is also a BSW-inch standard, the thread is also in inches, commonly known as Wyeth thread.
The metric thread is in MM (mm) and has a cusp angle of 60 degrees. Both US and inch threads are in inches. The cusp angle of the US thread is also 60 degrees, while the cusp angle of the inch thread is 55 degrees. Due to the different units of measurement, the representation of various threads is not the same. For example, the M16-2X60 represents a metric thread. His specific meaning is that the nominal diameter of the screw is 16MM, the tooth pitch is 2MM, the length is 60MM, and another example is: 1/4-20X3/4 means the inch thread, his specific meaning is the nominal diameter of the screw. It is 1/4 inch (one inch = 25.4 mm) with 20 teeth on one inch and 3/4 inches in length. In addition, if you want to indicate the US-made screws, you will usually add UNC and UNF to the back of the inch screws to distinguish between American-made coarse teeth and American-made fine teeth.
In the usual domestic sales business, the standards we most often encounter are GB (national standard) and DIN (German standard).
In terms of non-products, the following standards are mainly encountered: GB30; GB5783; GB5782; GB52; GB6170; GB818; GB819; GB845; GB846; GB70; DIN912; DIN933; DIN931. At present, GB30 (old national standard) has been replaced by GB5783 (new national standard) in the standard book. GB52 (old national standard) has been replaced by GB6170 (new national standard) in the standard book.
In 1986, our country set new standards for standard parts, which are commonly referred to as new standards in the business. The most used ones are GB5780, GB5781, GB5782, GB5783, and GB5784. GB5780 is a hexagonal thick rod half-screw screw, its accuracy grade is C-class product, can be replaced by GB5782 (GB5782 is a hex head thick rod full-tooth screw, its accuracy is grade A and B.) GB5781 is a hexagonal head The tooth screw has a precision grade of C grade. Can be replaced by GB5783 (GB5783 is a hexagonal head full-screw, its accuracy grade is A and B). GB5784 is a hexagonal screw with a thin rod and a half tooth.
The difference between the new standard and the old standard is that the products of the M8, M10, M12, M14, and M22 series differ in the width of the opposite side. In addition to the new products of the M22 series, the head-to-edge of the new standard products M8, M10, M12, and M14 is 1 mm smaller than the opposite side of the old standard. They are 13, 16, 18, 21MM, and the new products of the M22 series, the new standard is larger than the old standard, but should be 2MM. For the thickness of the head, there is a slight difference between the new standard and the old standard, and it can be used when the requirements are not very strict.
The difference between the new standard and the German standard is that the product specifications of the M10, M12, M14, and M22 differ in the width of the opposite side. The head-to-edge new standard of M10, M12, and M14 is 1mm smaller than the German standard. For the new product of the M22, the head-to-edge width is 2 mm larger than the width of the opposite side of the German standard, and the others can be used universally.
For hex nuts, the commonly used standards are: GB52, GB6170, GB6172 and DIN934. The main difference between them is: GB6170 is thicker than GB52, GB6172 and DIN934, commonly known as thick nuts. The other is the difference on the side, the opposite side of DIN934, GB6170, GB6172 in the M8 nut series is 13MM smaller than the opposite side of GB52 14MM, the nut of M10, the opposite side of DIN934 and GB52 is 17MM, The opposite side of GB6170 and GB6172 should be 1MM larger, the nut of M12, the opposite side of DIN934 and GB52 is 19MM larger than the opposite side of GB6170 and GB6172 18MM. For the M14 nut, the opposite side of DIN934 and GB52 is 22MM larger than the opposite side 21MM of GB6170 and GB6172. The other is the nut of M22, the opposite side of DIN934 and GB52 is 32MM, which is 2mm smaller than the opposite side of GB6170 and GB6172. (GB6170 and GB6172 are identical in width except for their different thicknesses.) The remaining specifications can be used without considering the thickness.
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Label: Thread 1986 US Precision Grade Screw
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